Geophysical surveying (e.g., seismic, electromagnetic) is a technique where two- or three-dimensional “pictures” of the state of an underground formation are taken. Geophysical surveying takes place not only on land, but also in marine environments (e.g., ocean, large lakes). Marine geophysical survey systems use a plurality of sensor streamers (long cables), which contain one or more sensors to detect acoustic energy emitted by one or more sources and reflected from the underground formation. Detection and interpretation of the signals represented thereby can be attenuated by destructive interference with reflections of the energy from interfaces present in the marine environment, particularly the water-air interface at the surface.
Discrimination against reflected signals may be provided by combining signals from multiple detector types sensitive to different physical characteristics of the acoustic signal. For example, when appropriately combined, the output from hydrophones sensitive to the pressure perturbation from the acoustic signal may be used in conjunction with the output of a detector sensitive to the velocity of a fluid particle for example, a geophone, may provide such discrimination. However, these detectors, particularly the geophone, typically are complex and concomitantly, costly to manufacture. Thus a low-cost device which may be used to provide similar capabilities would provide a competitive advantage in the marketplace.